1. Field of the Invention
The present invention relates to a light emitting element module equipped with a light emitting element and a manufacturing method thereof, as well as a backlight apparatus for use in a liquid crystal display device, such as a liquid crystal television or a liquid crystal monitor using the light emitting element module.
2. Description of the Related Art
Liquid crystal display devices, such as liquid crystal televisions and liquid crystal monitors, require a light source for illuminating the display from the rear, because the liquid crystal itself does not emit light. A solid state light emitting element, such as a fluorescent tube, or LEDs (light emitting diodes) is used as the light source, and in either case, measures for making the light uniform within the display area are required.
FIG. 6 shows a structure of a substrate equipped with a conventional light emitting element (light emitting element module). As disclosed in Japanese Unexamined Patent Publication 2008-305940, an LED 5 provided directly on a substrate 11, and the substrate 11 and the LED 5 are connected with wires 8, and furthermore, a cap 41 having a lens portion 41a and a reflector portion 41b that are molded together is bonded to the substrate using an adhesive resin 32 in order to protect the LED 5 and the wires 8, and moreover, a transparent sealing resin 42 is injected into the cap 41 and thermally cured, and thus the module is completed.
In the case of the above described related art, however, there is stress in the portion through which the cap 41 and the substrate 11 are bonded together, due to the difference in the coefficient of thermal expansion between the cap and the substrate (difference in the degree of thermal expansion/contraction) when the temperature changes, and a problem arises, such that the adhesive resin portion 32 between the substrate 11 and the cap 41 cracks and peels when the temperature changes repeatedly.
Furthermore, there is a problem with the precision in the border portion between the two color molds when the lens portion 41a and the reflector portion 41b in the cap are molded together, and this affects the yield. Moreover, the LED 5 is mounted on the substrate and connected with the wires 8, and thereafter molded in a resin by injecting a transparent liquid resin 42. As a result, there arises a problem such that bubbles are created or the resin foams when the transparent liquid resin 42 is injected into the cap 41 and thermally cured, which makes the yield of light emitting element modules very poor.